Layout tool



Sept. 27, 1955 o. F. KALBERER LAYOUT TOOL Filed Jan. '7, 1953 INVENTOR. OTTO F. KALBERER ATTORNEYS United .States Patent() LAYOUT TOOL Otto F. Kalberer, Warwick, R. I., assignor to Industrial Tool & Machine Co., a corporation of Rhode Island Application January 7, 1953, Serial No. 329,947

4 Claims. (Cl. 33189) i This invention relates to a layout tool and more particularly to a punch for locating the center of a drill which is used as one step in providing a tapped hole to hold a drill jig bushing although the tool may have other various and sundry uses.

In the centering of a drill for the use above indicated, often the punch used has a sleeve of such a size that it may be placed in the clearance space of the bushing to obtain the proper radial distance for the center of a headed screw to hold the bushing. When it is desired that a bushing of a different size be utilized which would use a screw having a different size head, a punch having a sleeve of a different radial distance would be similarly used for the different sized bushing.

One of the objects of this invention is to make a single layout tool which may be used for a plurality of sizes of bushings making unnecessary the production of a plurality of tools for this purpose.

Another object of this invention is to provide in a single tool, sleeve surfaces at varying radii for locating the tool in position.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out inY the appended claims.

In the accompanying drawings:

Figure l is a perspective view of a bed having a drill jig bushing located therein and my layout tool in position for locating the center of a drill as one step in providing a tapped hole in the bed;

Figure 2 is a sectional view on substantially line 2 2 of Figure 1;

Figure 3 is a view similar to Figure 2 but illustrating a bushing of smaller size;

Figure 4 is a sectional view on line 4-4 of Figure 3 showing the layout tool;

Figure 5 is a perspective view of a screw holding the bushing in position.

With reference to the drawings, designates a bed having an opening 11 therethrough into which a bushing 12 is positioned which has a bore 13 for guiding a drill. This bushing has a knurled head 14 so that it will provide a shoulder resting on the upper surface of the bed to limit its downward movement in the bed. In order to prevent the bushing from lifting out of the hole 11, it has a cut-away portion 15 providing a radially extending shoulder 16 as shown in Figures l and 2. This recess is further provided at one end with a clearance space 17 with no shoulder at this location. In order to hold lthis bushing in place, a screw 18 is positioned in a tapped hole with its head 19 so located that the shoulder 16 may be placed under the head to prevent the bushing from lifting upwardly as the drill is raised out of the bore 13. However, when it is desired to change from the bore 13 to a different size bore one bushing must be removed and another substituted. Then it is merely necessary to grip the bushing by the knurled head 14 and turn it until the clearance space 17 is lo- 2,718,708 Patented Sept. 27, 1955 ice ever, when the size of bore changes beyond acertain range, perhaps to a series of smaller bores, then a smaller size head, recess, and so forth, is used and will require a different size screw with a different size head to hold it in place, and the screw will beat a different distance from the axis of the bore.

In order to place the screw properly in place, the tool which is the subject of this invention and designated generally 20 is provided. This tool consists of a shank 21 of generally cylindrical diameter having a knurled upper portion 22 and provided with a central bore 23 extending axially throughout its length. Within this bore a marking punch 24 is positioned of a length longer than the shank so that it will protrude outwardly beyond the ends thereof. This punch is of the same cross sectional shape as the bore 23 and of a size to be slidably guided therein. The lower end of this punch is provided with a pointed end 25 which is on the axial center of the bore 23 in which it is guided, while its upper end 26' is blunt and adapted to receive a blow for driving the punch into the bed 10 to recess it sufciently for the initial starting of a drill therein.

The punch is cut away as at 28 to provide spaced abutments at either end of the recess, while a pin 29 is driven through the shank 21 in this recess so as to hold the punch in position against accidental removal from the shank.

In order to utilize the shank as a guide for the punch, I provide the outer surface of the shank 21 generally cylindrical. The lower portion 27 is on a radius along a sufficient portion of its surface so as to provide a locating surface for positioning the axial center of the punch 25 one correct distance a from the bushing, and the surface 31 is provided on a greater radius for the correct distance b from a larger bushing for the location of the hole to be tapped for the holding screw. I have shown this positioning surface 27 on substantially the same radius as the remainder of the shank 21. In the event, however, that it is desirable to utilize this layout tool for the larger size bushing such as shown at 12 in Figure 2, the surface 31 will be used as it is at the greater radius from the axial center of the bore. Thus, I position this surface 31 in the recess 17 of the larger size bushing 12 and locate the marking punch point 25 the proper distance from the clearance space 17 to provide a mark or starting prick punch for a drill the correct distance to take a larger size screw and larger size head for the larger bushing 12.

In the event, however, that it is desirable to utilize this layout tool for the smaller size bushing such as shown at 12' in Figure 3, the surface 27 will be used as it is at the smaller radius from the axial center of the bore. Thus, I position this surface 27 in the recess 17' of the smaller size bushing 12 and locate the marking punch point 25 the proper distance from the clearance space 17' to provide a mark or starting prick punch for a drill the correct distance to take a smaller size screw and smaller size head for the smaller bushing 12.

By this arrangement the same tool may be utilized for two different layouts, whereas heretofore two different tools having different radial guiding surfaces were necessary. From this principle it will be seen that a plurality of guiding surfaces may be provided on a tool, each at a different distance so as to adapt the single punch for use for a plurality of different layouts.

I claim:

1. A layout tool comprising an elongated shank having a longitudinal axial bore therethrough, a marking punch extending through said bore and guided thereby with a punch point at one end and a blow receiving end at the other, said punch point being directed along the longitudinal axis of said bore, said shank having a portion of its outer surface extending axially from the lower edge thereof and along an arc of one radius from said axis and another portion of its outer surface extending axially from said lower edge and along an arc of a different radius from said axis whereby one of the different arcuate surfaces may be'selected as a guide to lay out the distance that a center may be marked on a surface to be drilled.

2. Arlayout tool as in claim 1 wherein axially spaced abutments are located along the said punch and a mem- References Cited in the le of this patent UNITED STATES PATENTS Fisk July 17, 1917 Packer Oct. 23, 1928 

